A dual-sided composite microlens array myopia prevention and control lens, its hot embossing forming equipment and forming process

Abstract

The present invention discloses a myopia prevention and control lens with a double-sided composite microlens dense array and its hot embossing forming equipment and forming process. The hot embossing forming equipment includes an upper mold (1) and a lower mold (2); the upper mold (1) includes an upper template (9), an upper mold insert (10), a guide bushing (11), a positioning cone sleeve (12), and an upper mold electric heating rod mounting hole (13); the lower mold (2) includes a lower template (4), a lower mold insert (5), a guide post (6), a positioning cone (7), and a lower mold electric heating rod mounting hole (8). In the present invention, holes are drilled near the parting surface of the upper and lower molds, and the heating equipment is installed. The temperature difference on the product surface can be accurately controlled to ±0.5 - 1 °C. The present invention adopts hot embossing forming with a self-contained closed-loop temperature control system, which has high heating efficiency and high temperature control accuracy. The heating effect adjacent to the product surface is significantly better than the temperature control effect of existing general-purpose hot embossing forming machines, and can effectively solve the problems of dense array micro-convex mirror surfaces and array surface distortion, improving the product quality.

Description

Technical Field

[0001] The invention relates to a double-sided composite micro-lens dense array myopia prevention and control lens and a heating compression molding equipment and molding process thereof, belonging to the technical field of heating compression molding. Background Art

[0002] Survey data show that the myopia rate among middle school and college students in my country has exceeded 70% and is still increasing year by year. Even the myopia rate among primary school students is close to 40%. The myopia rate among Chinese teenagers aged 10-18 is the highest in the world. Myopia has a huge impact on both learning and life. Therefore, the myopia problem of children has become a widespread concern among parents.

[0003] The main cause of myopia is the growth of the eye axis of myopic patients, and over time the eye axis of myopic patients will continue to grow, exacerbating the degree of myopia. Studies have found that after correction with prevention and control lenses, the central area is imaged on the retina, and the peripheral area is projected in front of (or above) the retina, which helps to inhibit the lengthening of the eye axis. Especially for patients in the early stages of myopia, it can even induce the shortening of the eye axis. It is generally considered to be the most effective way to inhibit the aggravation of myopia.

[0004] In order to control the aggravation of myopia caused by the growth of the axial length of myopic patients, various forms of microlens dense array defocus lenses are currently available on the market. However, no matter whether it is a refractive microlens dense array or a diffractive microlens dense array or a dense array of various geometric distribution shapes (such as circular, elliptical, shell-shaped, etc.), they all face a common problem: the micro-convex mirror and the array surface are more or less distorted due to the characteristics of injection molding, which makes it difficult to accurately control the focal position of the light after refraction, and the overall optical performance and focusing effect cannot meet the requirements, resulting in an embarrassing situation where high cost cannot achieve the expected desired effect.

[0005] In fact, although a lot of research has been done on the density of dense microlens arrays (the number of microlenses in a single lens ranges from several hundred to nearly three thousand) and the geometric shape of the array surface (such as circular, elliptical, shell-shaped, etc.), the obtained product effect is not ideal. The fundamental reason is that the ideal solution is defeated by many problems during injection molding, such as the large shrinkage rate and fluctuation of the resin material, the anisotropy caused by the orientation of the molecular chain or the uneven heat distribution during the filling process, and the uneven product density caused by the post-filling (pressure holding) stage. Therefore, it is very necessary to explore a new molding method, molding process and molding equipment, and the heating compression molding of the present invention can well solve the above problems. Summary of the invention

[0006] One object of the present invention is to provide a hot embossing forming equipment that can effectively solve the distortion of the dense array of micro-convex mirrors and the array surface, has high production efficiency, low requirements for forming equipment, and high interchangeability and universality.

[0007] Another object of the present invention is to provide a stable, efficient, reproducible and popularizable forming process suitable for the forming method and forming equipment described in the first object.

[0008] A third object of the present invention is to provide a double-sided composite micro-lens dense array myopia prevention and control lens with overall optical performance and focusing effect meeting the requirements.

[0009] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0010] A hot embossing forming equipment for a double-sided composite micro-lens dense array myopia prevention and control lens, including a matching upper mold and a lower mold;

[0011] The upper mold includes an upper template, and a number of upper mold inserts are movably inlaid on the lower surface of the upper template. A number of guide sleeves and a number of positioning cone sleeves are also provided on the upper template; a number of upper mold electric heating rod mounting holes are provided on the side surface of the upper template near the lower surface of the upper template and at the corresponding positions of the upper mold inserts.

[0012] The lower mold includes a lower template, and a number of lower mold inserts are movably inlaid on the upper surface of the lower template. A number of guide posts adapted to the guide sleeves and a number of positioning cones adapted to the positioning cone sleeves are also provided on the lower template; a number of lower mold electric heating rod mounting holes are provided on the side surface of the lower template near the upper surface of the lower template and at the corresponding positions of the lower mold inserts.

[0013] Electric heating rods are installed in both the upper mold electric heating rod mounting holes and the lower mold electric heating rod mounting holes. A temperature detecting device is provided on the lower surface of the upper template or the upper surface of the lower template. The temperature detecting device is connected to a closed-loop intelligent temperature control system, and the closed-loop intelligent temperature control system is connected to the electric heating rods.

[0014] In the present invention, the electric heating rods, the temperature detecting device and the closed-loop intelligent temperature control system are all powered by a power supply; the power supply can be commercial power or a storage battery. The temperature detecting device can be a commercially available temperature sensor.

[0015] The working surface of the upper mold insert is a plane, and the working surface of the lower mold insert is a convex spherical surface with a concave spherical surface distributed in a dense array (the concave spherical surface distributed in a dense array is an irregular spherical surface, with a size of about 0.5 - 0.8 mm).

[0016] The lower surface of the upper template and the upper surface of the lower template are both provided with groove-shaped mold frames, and a plurality of the upper mold inserts or lower mold inserts are press-fitted into the corresponding mold frames with an interference fit of H7 / r6.

[0017] The electric heating rod is a CIA-7 series electric heating rod with a specification of Φ12×300mm; the heating density is 60W / cm 2 .

[0018] The model of the closed-loop intelligent temperature control system is Kistler, ComoNeo and ComoScout - process monitoring and control systems, 5887A.

[0019] A sheet material is placed between the upper mold insert and the lower mold insert, and the raw material of the sheet material includes at least one of MDI, TDI, PMMA, PC, and PS.

[0020] A forming process of a heating and molding equipment for a double-sided composite microlens array myopia prevention and control lens includes the following steps:

[0021] Step 1: After the heating and molding equipment is installed and fixed, adjust and set the stroke of the movable slider of the hydraulic press.

[0022] Step 2: After debugging, during production, the heating time is controlled by the closed-loop intelligent temperature control system. After the sheet material is heated and softened, the movable slider of the hydraulic press descends to apply pressure, completes the forming and maintains the pressure for a period of time. After the formed sheet material is stable, the movable slider of the hydraulic press ascends, and the upper mold and the lower mold open.

[0023] Step 3: The formed sheet material has a small resistance to demolding and is easy to demold, and the formed sheet material is taken out.

[0024] Step 4: Then it is placed on a blanking die to complete blanking to obtain the product.

[0025] In Step 3, the formed sheet material is taken out manually or by a mechanical arm with a suction cup.

[0026] In Step 4, the blanking process is cold stamping.

[0027] The closed-loop intelligent temperature control system controls the temperature at 90 - 110°C, the heating time at 2 - 4s, the forming speed of the hydraulic press at 5 - 13mm / s, the forming pressure and the holding pressure at 1 - 3Mp and 1 - 1.8Mp respectively, and the holding time at 1.5 - 3.5s.

[0028] A double-sided composite microlens array myopia prevention and control lens obtained by a heating and molding equipment for a double-sided composite microlens array myopia prevention and control lens.

[0029] Advantages of the present invention:

[0030] 1. The upper die insert and the lower die insert of the present invention adopt an interference fit of H7 / r6 and are installed and fixed together by the temperature difference fitting method to form an arrangement mode of "one die with multiple cavities". This design has the following beneficial effects: (1) The multi-cavity layout can improve production efficiency and thus reduce costs; (2) The overall inlay and splicing make the assembly error not affect the forming accuracy of the microlens array. At the same time, in the production process, once a special situation causes damage to the forming part insert, it can be replaced with a spare part. The interchangeability is good, and the production will not be delayed; (3) If a large hydraulic equipment is selected, the number of cavities may be increased, resulting in too large upper and lower template sizes and difficult to process. The inlay and splicing structure can well solve this problem.

[0031] 2. The present invention drills holes near the parting surface of the upper and lower dies and installs heating equipment of appropriate specifications. The temperature difference on the product surface can be accurately controlled within ±0.5°C - 1°C. This design has the following beneficial effects: (1) The existing special or general heating and molding presses with built-in heating and temperature control systems are expensive and require a large equipment investment, while the equipment of the present invention is low in price; (2) The present invention adopts a semi-separated mode of the equipment and the temperature control system, which can reduce the later equipment maintenance cost; (3) The present invention can select heating and temperature control auxiliary equipment more flexibly and efficiently. The present invention adopts heating and molding with a built-in closed-loop temperature control system, which has high heating efficiency and high temperature control accuracy. The heating effect adjacent to the product surface is significantly better than the temperature control effect of the existing general heating and molding machines, and can effectively solve the distortion of the dense array of micro-convex mirror surfaces and array surfaces, improving the product quality.

[0032] 3. The present invention can form multiple lenses at one time (depending on the size of the hydraulic press workbench), greatly improving the production efficiency. The process parameters of the present invention have small fluctuations and the rejection rate of forming multiple spectacle lens surfaces at one time is low. It has good operability and reproducibility, which is conducive to promotion.

[0033] 4. The guiding of the guide pillar / guide sleeve of the present invention can guide the upper and lower dies at the initial stage of closing, preventing misalignment of the upper and lower forming inserts and improving the service life of the equipment; the standard parts of the sliding guide pillar and guide sleeve of the present invention generally adopt a clearance fit of H7 / f8, and its positioning accuracy is poor. Adding positioning cones can greatly improve the positioning accuracy of the upper and lower dies, preventing distortion of the micro-convex structure caused by misalignment. If manual feeding is used, the four positioning cones of the present invention can also assist the operator to quickly place the cut blank in the correct position, playing an auxiliary role in quickly placing the blank. Description of the drawings

[0034] Figure 1 Structural schematic diagram of a myopia lens with double concave lens surfaces;

[0035] Figure 2 For Figure 1 Top view;

[0036] Figure 3 is Figure 2 an enlarged view of part A in

[0037] Figure 4 a schematic structural view of the hot press forming equipment in the present invention;

[0038] Figure 5 a schematic structural view of the upper mold in the present invention;

[0039] Figure 6 a schematic structural view of the lower mold in the present invention;

[0040] Figure 7 a schematic structural view of the upper mold insert in the present invention;

[0041] Figure 8 a schematic structural view of the lower mold insert in the present invention. Detailed implementation manners

[0042] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0043] Embodiment 1

[0044] As Figures 1 to 3 shown, the myopia defocus lens with a micro-lens dense array is composed of a stack 14 (one side is a concave lens surface and the other side is a flat surface) and a stack 15 (one side is a concave lens surface and the other side is a flat surface with a dense array of aspherical micro-protrusions). A myopia lens with a double-sided concave lens surface is formed by adhesively sealing the flat sides of the two stacks. The product of the present invention is the stack 15, and for the convenience of understanding, this patent refers to the stack 15 as the lens. The myopia defocus lens with a micro-lens dense array is densely distributed with aspherical micro-protrusions that change the curvature in the dense array control area (refraction angle control area). In traditional injection molding, it is difficult to avoid the generation of settlement spots (i.e., one side is convex and the other side is concave) on the back of the convex position due to the sudden change in the wall thickness of the lens. The back settlement spots will also cause the curvature of the dense array of aspherical surfaces to be distorted, making it difficult to control the refraction direction of the product light, and thus resulting in an unsatisfactory control effect. The hot press forming with a self-contained closed-loop temperature control system adopted by the present invention can avoid the above defects to the greatest extent and improve the product quality.

[0045] In this embodiment, a hot press forming method is adopted to propose a hot press forming equipment, and its structure is as Figure 4 shown. This equipment can be optionally equipped with a heating equipment (SAKAGUCHI CIA-7 series electric heating rods from Japan, specification Φ12×300mm, heating density 60W / cm 2) and a closed-loop intelligent temperature control system (Kistler, ComoNeo and ComoScout - process monitoring and control systems, 5887A), the temperature difference on the product surface can be accurate to ±0.5°C - 1°C. In the existing general - type heating and molding press, the heating device is generally placed in the lower workbench and the upper slider of the press, and its disadvantages of low heating efficiency and low temperature control accuracy are difficult to overcome. However, in this equipment, the heating device is directly placed in the electric heating rod installation holes pre - machined in the upper template 9 and the lower template 4, close to the product surface. The heating effect is significantly better than the temperature control effect of the general - type heating and molding press, and it is easier to accurately control the temperature fluctuation of the sheet material surface than the traditional method, and the heating is uniform, thus ensuring the quality of each lens product (greatly reducing the defective rate); the existing heating and molding press is a special equipment with a high price. This equipment can be installed on an ordinary hydraulic press for production, and its universality is significantly better than that of the traditional heating and molding die.

[0046] The forming parts of a heating and molding equipment for double - sided composite micro - lens array myopia prevention and control lenses adopt a mosaic structure. As Figures 5 to 6 shown, both the upper template 9 and the lower template 4 are framed, and the forming inserts (each set of forming inserts consists of Figure 7 the upper die insert 10 shown as Figure 8 and the lower die insert 5 shown as

[0047] shown, corresponding to the core and cavity of one lens) are installed and fixed together by an interference fit of H7 / r6 and the temperature - difference fitting method to form a "multi - cavity in one mold" layout. This design mainly considers the following points: (1) The multi - cavity layout can improve production efficiency and thus reduce costs; (2) Using an overall mosaic structure makes the assembly error not affect the forming accuracy of the micro - lens array. At the same time, in the production process, once a special situation causes damage to the forming part insert, it can be replaced with a spare part. The interchangeability is good, and production will not be delayed; (3) If a large - scale hydraulic equipment is selected, the number of cavities may be increased, resulting in too large upper and lower template sizes and difficult processing. The mosaic structure can solve this problem well.

[0048] A heating and compression molding equipment for double-sided composite micro-lens dense array myopia prevention and control lenses adopts a guide post / guide sleeve guidance and positioning cone precision positioning design. This design mainly takes into account: (1) The guide post / guide sleeve can guide the upper and lower molds in the initial closing stage to prevent the upper and lower molding inserts from being misaligned, thereby increasing the life of the equipment; (2) The standard parts of the sliding guide post and guide sleeve generally use a clearance fit of H7 / f8, and their positioning accuracy is poor. Adding a positioning cone can greatly improve the positioning accuracy of the upper and lower molds to prevent the micro-convex structure of the lens from being distorted due to misalignment. (3) If manual feeding is used, the four positioning cones can also assist the operator to quickly place the cut sheet in the correct position, which plays an auxiliary role in the rapid placement of the sheet.

[0049] A heating and compression molding process for a double-sided composite micro-lens dense array myopia prevention and control lens mainly includes the following steps:

[0050] (1) The raw materials of the sheet include at least one of polyurethane resin (MDI, TDI, etc.), PMMA (polymethyl methacrylate), PC (polycarbonate), and PS (polystyrene). The sheet can be cut to the specified size using an electric jigsaw, electric circular saw, electric hot wire cutter, or a special sheet cutting machine.

[0051] (2) The heating compression molding equipment consists of two half molds, the upper and lower molds. In order to facilitate the connection and fixation of the equipment with the hydraulic press, the equipment is designed into an "I" structure. The equipment is placed at an appropriate position on the hydraulic press workbench. The T-slot or dovetail groove of the hydraulic press workbench is used, and four standard pressing plates (mold-coding devices) are used to press and fix the upper mold fixing plate and the lower mold fixing plate of the equipment on the lower slide block and the workbench surface of the hydraulic press to complete the installation of the equipment.

[0052] (3) After the equipment is installed and fixed, adjust and set the stroke of the movable slide of the hydraulic press. On the premise that it is convenient to place the pre-molding sheet and take out the post-molding sheet, the stroke of the hydraulic press should be as small as possible, which can reduce the "idle running" time and improve the heating efficiency.

[0053] (4) After the equipment is debugged, during production, the closed-loop intelligent temperature control system determines the set heating time, the heating and softening are completed, the hydraulic press slider moves downward to apply pressure to complete the molding and maintain the pressure for a period of time. After the product is stable, the slider moves upward, and the upper and lower molds are opened. At this time, due to the plastic flow of the sheet metal toward the die insert under pressure, the outer dimensions of the sheet metal will become smaller. At the same time, due to the small thickness of the product (depending on the degree of axial growth, generally between 0.3-0.8mm) and the curved surface design of the product, the formed sheet metal can be taken out manually or by a robotic arm with a suction cup.

[0054] (5) The taken sheet metal is then placed on the blanking die to complete blanking and obtain the product. Since the blanking process belongs to cold stamping, it has minimal impact on the microlenses of the lens and their display surfaces and will not cause distortion.

[0055] In this embodiment, multiple lenses can be formed at one time (depending on the size of the hydraulic press workbench), greatly improving the production efficiency.

[0056] In addition, this embodiment also proposes a hot embossing forming process for double-sided composite microlens array myopia defocus lenses. The process parameters have small fluctuations, the rejection rate of the mirror surfaces of multiple spectacle lenses formed at one time is low, the operability and replicability are good, and it is conducive to popularization.

[0057] Specifically, a hot embossing forming equipment for double-sided composite microlens array myopia prevention and control lenses includes a matching upper die 1 and lower die 2; the upper die 1 includes an upper template 9, upper die inserts 10, guide sleeves 11, positioning cone sleeves 12, and upper die electric heating rod mounting holes 13; the lower die 2 includes a lower template 4, lower die inserts 5, guide posts 6, positioning cones 7, and lower die electric heating rod mounting holes 8.

[0058] Specifically, the upper die 1 includes an upper template 9. A number of upper die inserts 10 are movably embedded on the lower surface of the upper template 9. A number of guide sleeves 11 and a number of positioning cone sleeves 12 are also provided on the upper template 9; a number of upper die electric heating rod mounting holes 13 are provided on the side surface of the upper template 9 near the lower surface of the upper template 9 and at the corresponding positions of the upper die inserts 10;

[0059] The lower die 2 includes a lower template 4. A number of lower die inserts 5 are movably embedded on the upper surface of the lower template 4. A number of guide posts 6 adapted to the guide sleeves 11 and a number of positioning cones 7 adapted to the positioning cone sleeves 12 are also provided on the lower template 4; a number of lower die electric heating rod mounting holes 8 are provided on the side surface of the lower template 4 near the upper surface of the lower template 4 and at the corresponding positions of the lower die inserts 5;

[0060] Electric heating rods are installed in both the upper die electric heating rod mounting holes 13 and the lower die electric heating rod mounting holes 8. A temperature detecting device is provided on the lower surface of the upper template 9 or the upper surface of the lower template 4. The temperature detecting device is connected to a closed-loop intelligent temperature control system, and the closed-loop intelligent temperature control system is connected to the electric heating rods.

[0061] The working surface of the upper die insert 10 is a plane, and the working surface of the lower die insert 5 is a convex spherical surface with a concave spherical surface distributed in a dense array; because the processing accuracy requirements for the forming part of the lower die insert 5 are high (the dimensional error is less than 0.2 μm, and the surface finish is less than 3 nm), generally a single-point diamond lathe is required for processing the micro-lens dense array. At the same time, due to price issues, most of the single-point diamond lathes on the market are small, with a small milling stroke, and the size of the workpieces that can be processed is generally less than 200 mm. Therefore, the upper template 9 of the upper die 1 adopts a mosaic structure. The upper template 9 is framed to install and fix multiple upper die inserts 10 by interference fit of H7 / r6 and the temperature difference fitting method (in this equipment, 15 upper die inserts 10 are embedded in the die frame). At the same time, the lower template 4 of the lower die 2 also adopts a mosaic structure. The lower template 4 is framed to install and fix multiple lower die inserts 5 by interference fit of H7 / r6 and the temperature difference fitting method (in this equipment, 15 lower die inserts 5 are embedded in the die frame). The beneficial effect is that the overall mosaic makes the assembly error not affect the forming accuracy of the micro-lens dense array, and the mosaic structure has good interchangeability. Among them, the size of the upper template 9 can be adjusted according to the size of the hydraulic press workbench and the upper die insert 10, and the number of forming inserts can be flexibly adjusted, so as to further improve production efficiency. The same principle applies to the lower template 4 of the lower die 2 adopting a mosaic structure.

[0062] The guide bush 11 of the upper die 1 and the guide post 6 of the lower die 2 play a role in opening and closing guidance to ensure the service life of the equipment. The positioning cone sleeve 12 of the upper die 1 and the positioning cone 7 of the lower die 2 can ensure that the upper and lower half dies do not shift out of position and affect the dimensional accuracy during lens forming. At the same time, the positioning cone 7 of the lower die 2 can also help the operator to position when placing the sheet material.

[0063] A double-sided composite micro-lens dense array myopia prevention and control lens obtained by a heating and molding equipment for double-sided composite micro-lens dense array myopia prevention and control lenses.

[0064] Specifically, in this embodiment, taking the heating and molding production of 0.5 mm thick PMMA sheet as an example (the given molding equipment in this embodiment is a 15-cavity mold, and the sheet material needs to be cut into a size of 245 mm × 220 mm. The specific cutting size depends on the number of cavities per mold and the layout method), the forming process parameters of each embodiment are shown in Table 1.

[0065] In this embodiment, the temperature of the temperature control electric box is set to 90 °C, the heating time is set to 2 s, the forming speed of the press is set to 5 mm / s, the forming pressure and the holding pressure are 1 Mp and 1 Mp respectively, and the holding time is 1.5 s. The polymethyl methacrylate sheet is cut into the specified size by an electric heating wire cutter (the cut is relatively neat) and manually placed into the heating and molding equipment, and the lens sample is obtained through heating and molding and blanking processing.

[0066] Example 2

[0067] The difference between this embodiment and Embodiment 1 is only that: the temperature of the temperature control electric box is set to 95 °C, the heating time is set to 2.5 s, the forming speed of the press is set to 7 mm / s, the forming pressure and the holding pressure are 1.5 Mp and 1.2 Mp respectively, and the holding time is 2 s. A lens sample is obtained with reference to the forming process flow of Embodiment 1.

[0068] Embodiment 3

[0069] The difference between this embodiment and Embodiment 1 is only that: the temperature of the temperature control electric box is set to 100 °C, the heating time is set to 3 s, the forming speed of the press is set to 9 mm / s, the forming pressure and the holding pressure are 2 Mp and 1.4 Mp respectively, and the holding time is 2.5 s. A lens sample is obtained with reference to the forming process flow of Embodiment 1.

[0070] Embodiment 4

[0071] The difference between this embodiment and Embodiment 1 is only that: the temperature of the temperature control electric box is set to 105 °C, the heating time is set to 3.5 s, the forming speed of the press is set to 11 mm / s, the forming pressure and the holding pressure are 2.5 Mp and 1.6 Mp respectively, and the holding time is 3 s. A lens sample is obtained with reference to the forming process flow of Embodiment 1.

[0072] Embodiment 5

[0073] The difference between this embodiment and Embodiment 1 is only that: the temperature of the temperature control electric box is set to 110 °C, the heating time is set to 4 s, the forming speed of the press is set to 13 mm / s, the forming pressure and the holding pressure are 3 Mp and 1.8 Mp respectively, and the holding time is 3.5 s. A lens sample is obtained with reference to the forming process flow of Embodiment 1.

[0074] Table 1 Setting table of each implementation process parameters for hot pressing forming of polymethyl methacrylate sheet (0.5 mm)

[0075]

[0076]

[0077] The lens samples of Embodiments 1 - 5 are sent to a professional third - party testing agency to detect each key parameter, and the test results are shown in Table 2. Comparing the key parameters of the samples with the parameters of the injection - molded products of the same material published by a certain brand, it is not difficult to see that:

[0078] Comparison of the data of tensile strength (a key index to measure the anti-destruction ability of the lens; the higher the tensile strength, the less likely the lens is to be damaged) and elongation at break (a key index to measure the toughness of the lens; the greater the elongation at break, the better the toughness of the lens, and the less likely it is to be bumped, pressed, broken or even shattered) in the test items shows that the tensile strength and elongation at break of the products of Examples 1 to 5 are generally higher than those of the injection molded products announced by a certain brand, indicating that the toughness of the products of Examples 1 to 5 is better than that of the injection molded products announced by a certain brand, and the products are more resistant to collision. Once hardened coating is applied, the service life of the products of Examples 1 to 5 will have a more obvious advantage.

[0079] In the test project, the refractive index (refractive index is an important parameter that reflects the efficiency of the lens in refraction of light. The larger the refractive index, the higher the efficiency of light correction. However, the higher the refractive index, the more serious the dispersion and blurred vision) data comparison shows that the refractive index of the products of Examples 1 to 5 is significantly lower than that of the injection molded products announced by a certain brand, and the density of the products of Examples 1 to 5 is significantly higher than that of the injection molded products announced by a certain brand, indicating that the clarity of the products of Examples 1 to 5 is significantly superior to that of the injection molded products announced by a certain brand. Although the higher the refractive index, the stronger the adjustment ability, or the thinner the lens can be; but too high a refractive index can easily cause reflection of light, making the vision blurred. It can be seen that the refractive index of the lens of the present invention is lower than that of the injection molded products announced by a certain brand and the refractive index is moderate, so the vision is clear.

[0080] Comparison of the Abbe number data in the test project shows that the Abbe number (also known as the "dispersion coefficient", which is the main parameter for measuring the degree of light dispersion of a transparent medium. The greater the refractive index of the medium, the more severe the dispersion, the smaller the Abbe number, the blurrier the vision) of the products of Examples 1 to 5 is slightly higher than that of the injection molded products published by a certain brand. This also shows that the dispersion of the products of Examples 1 to 5 has a clear advantage over the injection molded products published by a certain brand, that is, the vision is clearer.

[0081] Table 2 Test results of Example 1-Example 5

[0082]

[0083]

[0084] It should be understood that, in order to streamline the present disclosure and assist in understanding one or more of the various inventive aspects, in the foregoing description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected by the claims, the inventive aspects lie in less than all of the features of the previously disclosed embodiments. Thus, the claims following the detailed description hereby expressly incorporate the detailed description, where each claim itself serves as a separate embodiment of the present invention.

[0085] Although the present invention has been described in terms of a limited number of embodiments, those skilled in the art in this technical field will appreciate, upon the foregoing description, that other embodiments can be contemplated within the scope of the invention thus described. In addition, it should be noted that the language used in this specification has been principally selected for readability and instructional purposes and not for the purpose of explaining or limiting the subject matter of the invention. Accordingly, many modifications and variations will be apparent to those of ordinary skill in this technical field without departing from the scope and spirit of the appended claims. For the scope of the present invention, the disclosure of the present invention is illustrative, not restrictive, and the scope of the present invention is defined by the appended claims.

[0086] The foregoing are only the preferred embodiments of the present invention, and it should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A heating and molding equipment for a double-sided composite microlens dense array myopia prevention and control lens, characterized in that, it includes a matching upper mold (1) and a lower mold (2); The upper mold (1) includes an upper template (9). A number of upper mold inserts (10) are movably embedded on the lower surface of the upper template (9). A number of guide sleeves (11) and a number of positioning cone sleeves (12) are also provided on the upper template (9). A number of upper mold electric heating rod mounting holes (13) are provided on the side surface of the upper template (9) near the lower surface of the upper template (9) and at the corresponding positions of the upper mold inserts (10); The lower mold (2) includes a lower template (4). A number of lower mold inserts (5) are movably embedded on the upper surface of the lower template (4). A number of guide posts (6) adapted to the guide sleeves (11) and a number of positioning cones (7) adapted to the positioning cone sleeves (12) are also provided on the lower template (4). A number of lower mold electric heating rod mounting holes (8) are provided on the side surface of the lower template (4) near the upper surface of the lower template (4) and at the corresponding positions of the lower mold inserts (5); Electric heating rods are installed in both the upper mold electric heating rod mounting holes (13) and the lower mold electric heating rod mounting holes (8). A temperature detecting device is provided on the lower surface of the upper template (9) or the upper surface of the lower template (4). The temperature detecting device is connected to a closed-loop intelligent temperature control system, and the closed-loop intelligent temperature control system is connected to the electric heating rods; The working surface of the upper mold insert (10) is a plane, and the working surface of the lower mold insert (5) is a convex spherical surface with a concave spherical surface distributed in a dense array; Groove-shaped mold frames are opened on the lower surface of the upper template (9) and the upper surface of the lower template (4). A number of the upper mold inserts (10) or lower mold inserts (5) are embedded in the corresponding mold frames by an interference fit of H7 / r6.

2. The heating and molding equipment for a double-sided composite microlens dense array myopia prevention and control lens according to claim 1, characterized in that, the electric heating rod is a CIA-7 series electric heating rod.

3. A heating and molding equipment for a double-sided composite microlens dense array myopia prevention and control lens according to claim 1, characterized in that, a sheet material is placed between the upper mold insert (10) and the lower mold insert (5). The raw material of the sheet material includes at least one of MDI, TDI, PMMA, PC, and PS.

4. A molding process using the heating and molding equipment for a double-sided composite microlens dense array myopia prevention and control lens according to any one of claims 1 to 3, characterized in that, it includes the following steps: Step 1, after the heating and molding equipment is installed and fixed, adjust and set the stroke of the movable slider of the hydraulic press; Step 2, after debugging, during production, the heating time is controlled by the closed-loop intelligent temperature control system. After the sheet material is heated and softened, the movable slider of the hydraulic press descends to apply pressure, completes the molding and maintains the pressure for a period of time. After the molded sheet material is stable, the movable slider of the hydraulic press ascends, and the upper mold (1) and the lower mold (2) are opened; Step 3, the molded sheet material has little resistance to demolding and is easy to demold. Take out the molded sheet material. Step 4: Then place it on the blanking die to complete blanking and obtain the product.

5. The forming process according to claim 4, characterized in that, in Step 3, the formed sheet is taken out manually or by a robotic arm with a suction cup.

6. The forming process according to claim 4, characterized in that, in Step 4, the blanking process is cold stamping.

7. The forming process according to claim 5, characterized in that, the closed-loop intelligent temperature control system controls the temperature at 90 - 110 °C, the heating time is 2 - 4 s, the forming speed of the hydraulic press is 5 - 13 mm / s, the forming pressure and the holding pressure are 1 - 3 Mp and 1 - 1.8 Mp respectively, and the holding time is 1.5 - 3.5 s.

8. A double-sided composite microlens array myopia prevention and control lens obtained by using the heating and molding equipment for the double-sided composite microlens array myopia prevention and control lens according to any one of claims 1 - 3.

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